Radiative heat transfer between nanostructured objects is a new prolific research line, which open to new heat transfer modulation and amplification possibilities. We will consider the heat transfer between micro/nano-gratings. In particular, we calculate the radiative heat transfer between two identical metallic one-dimensional lamellar gratings [1]. To this aim we present and exploit a modification to the widely-used Fourier modal method, known as adaptive spatial resolution, based on a stretch of the coordinate associated to the periodicity of the grating. We first show that this technique dramatically improves the rate of convergence when calculating the heat flux, allowing to explore smaller separations. We then present a study of heat flux as a function of the grating height, highlighting a remarkable amplification of the exchanged energy, ascribed to the appearance of spoof-plasmon modes, whose behavior is also spectrally investigated. Differently from previous works, our method allows us to explore a range of grating heights extending over several orders of magnitude. By comparing our results to recent studies we find a consistent quantitative disagreement with some previously obtained results going up to 50%. In some cases, this disagreement is explained in terms of an incorrect connection between the reflection operators of the two gratings.

We investigate the transport of energy in a linear chain of two-level quantum emitters ("atoms")weakly coupled to a blackbody radiation bath [1]. We show that, simply by displacing one ormore atoms from their regular-chain positions, the efficiency of the energy transport can beconsiderably amplified of at least one order of magnitude. Besides, in configurations providingan efficiency greater than 100% , the distance between the two last atoms of the chain canbe up to 20 times larger than the one in the regular chain, thus achieving a much longer-rangeenergy transport. By performing both a stationary and time-dependent analysis, we ascribethis effect to an elementary block of three atoms, playing the role of excitation injector fromthe blackbody bath to the extraction site. By considering chains with up to 7 atoms, we alsoshow that the amplification is robust and can be further enhanced up to 1400%.-------------------------[1] P. Doyeux, R. Messina, B. Leggio, and M. Antezza, Phys. Rev. A 95, 012138 (2017).

The control of structuring and morphology in hybrid solids is a key parameter for the design of functional materials. In particular, it has been shown that structure and morphology could be tuned through sol gel synthesis conditions in bridged silsesquioxanes (BS). As a matter of fact, during sol-gel process, the competition between self-assembing through non covalent interactions between the organic sub-structures and condensation of the inorganic siliceous sub-structure can lead to the formation of crystalline compounds or amorphous materials.In order to go further with the understanding of the control of the nanostructuring in bridged silsequioxane, we designed the organic moieties of the precursors with either 2 symetrical through hydrogen bond and the strength of these hydrogen bonds is studied through vibrational spectroscopies in-situ at low temperature or at high pressure. The results are analyzed and discussed in terms of H bond strength and geometric factors.In the second part of this talk, we will focus on the influence of the central subunit lying between the two urea/thiourea groups_either a long flexible alkyl chain or rigid phenyl group_ on the self-assembling properties through H bonds.

We investigate spontaneous and pumped entanglement of two level systems in the vicinity of a photonic topological insulator interface, which supports a nonreciprocal (unidirectional), scattering-immune and topologically-protected surface plasmon polariton in the bandgap of the bulk material [1]. To this end, we derive a master equation for qubit interactions in a general three-dimensional, nonreciprocal, inhomogeneous and lossy environment. The environment is represented exactly, via the photonic Green function. The resulting entanglement is shown to be extremely robust to defects occurring in the material system, such that strong entanglement is maintained even if the interface exhibits electrically-large and geometrically sharp discontinuities. Alternatively, depending on the initial excitation state, using a non-reciprocal environment allows two qubits to remain unentangled even for very close spacing. The topological nature of the material is manifest in the insensitivity of the entanglement to variations in the material parameters that preserve the gap Chern number. Our formulation and results should be useful for both fundamental investigations of quantum dynamics in nonreciprocal environments, and technological applications related to entanglement in two-level systems.

Bridged silsesquioxane nanomaterials exhibit original mechanical properties thanks to the association of non-covalent and covalent interactions. Thanks to in situ high pressure spectroscopic studies, achieved in diamond anvil cells, the mechanical behavior of these materials was followed as a function of pressure. Vibrational studies coupled to ab-initio simulations show that mechanical constrains are absorbed by the modulation of H bond interactions. We thus show that the rigidity yielded by the inorganic polymerization is counterbalanced by the presence of the intermolecular H bond network. In a large range of pressures, these hybrid materials have a reversible behavior, and thus behave as molecular springs. In a second time, we demonstrate that the pressure behavior of these molecular spring is sensitive to the conformation of H bonds (cyclic versus linear) and to the constraints imposed the covalent inorganic network.

Bulk films and heterostructures based on HgCdTe compounds can be engineered to fabricate “gapped-at-will” structures. Therefore, 1D, 2D and even 3D massless particles can be observed in topological phase transitions driven by intrinsic (quantum well thickness, Cd content) and external (magnetic field, temperature, strain or hydrostatic pressure) physical parameters. In this work, we report on our experimental results, obtained by temperature-dependent Terahertz and Mid-Infrared magneto-spectroscopy, of topological phase transitions in HgCdTe-based Quantum Wells and bulk films. These transitions are accompanied with the appearance of 2D and 3D massless particles called Dirac and Kane fermions, respectively.